Monday, January 4, 2016

How to Germinate Seeds Using Soil Blocks Recommended by Eliot Coleman and Barbara Damrosch

Getting started

In order for seeds to germinate properly, and seedlings to grow robustly indoors, you need to have bottom heat for germination, lights or natural sunlight in a south facing window, warm ambient temperatures, and plenty of fresh air. There is no substitution for any one of these requirements. You have to prepare the space to germinate seeds, and then have that space slightly expandable for seedling growth.

Let me walk you through your seed starting setup. You will want to have:

  • Trays
  • Soil
  • Seeds
  • Labels
  • Graph Paper
  • Water Misters.


Step 1: Seed sprouting temperatures.
The Heat Mat

block trayYou have your seed packets, you've made your blocks, now what? You need to germinate them at precisely the right temperature indicated on the seed pack. You may need to encourage germination with a heat mat and thermostat. Since seeding is scientific and nature eventually provides the right temperature at the right time. Doesn't it make sense to duplicate this process with a precision control for fast, vigorous, high germination rates?

Some plants never get off to good start, and they never yield the way they should have. Most of time, it is because the seed didn't germinate properly under the right temperatures. Since soil blocks already have soil, air, moisture, and darkness with a cover or pinch of soil, the only block take care of the seedling, but you must make it sprout with precision temperatures.

It is true that a variety of seeds will sprout under a broad spectrum of temperatures, but have you ever noticed that there is always one certain degree that is indicated in the plant's preference? That is what you must shoot for. You have to go for that one precise temperature for the biggest, best, healthiest plants imaginable. Plant your seeds and set your temperatures. Know when they should germinate and check them out periodically.

Click here for our soil block size, pin, and temperature settings for vegetables.

See our best blog article on Trays to place on your heat mat.


Step 2: Lighting.
Cost efficient bright full spectrum light

maxlume200wAfter your sprouts come up they are looking for light, and lots of it! Where are your seedlings now? They could be very happy in a south-facing window. Anywhere else and they are going to get very leggy and spindly, and that won't help them.

Or maybe you have some lights? You need real grow lights with a full sprectrum bulb.

Fluorescent tube bulbs/lamps are fine if they're placed directly above the seedling. You have to let the leaves touch the bulb for maximum light absorption.

Compact Florescent bulbs in reflective fixtures are even better.

Incandescent bulbs are great if there's enough wattage and spaced far enough away so they don't burn the leaves.

And High Intensity Discharge lights or Metal Halides and High Pressure Sodium fixtures are best, but very expensive, and technical issues will have to be covered later. But the key point is to get the bang out of your buck by getting more lumens or foot candles per watt. And then, use 50 watts per square foot of seedling space.

How long of light do they need? Most seedlings will require a minimum of 14 hours a day. Maximum can be 18 hours a day. Since your mimicking nature, 14 hours signals "springtime" and more than 18 is unnecessary, as the plant isn't going to use that properly without being "pushed" with other growth stimulants.


Step 3: Air.
Fan Convenience

clip fanAgain, Nature does it best with fresh air. So vent properly your space and draw in fresh air and exit hot stale air. Fresh air should be drawn in from the bottom, where it's cool and laden with oxygen, and hot air should be vented from the top, as heat rises.

Got Fans??? If you don't have fans blowing your seedlings "back and forth" and "bobbing up and down and nodding with anthropomorphic approval", please do so NOW. It is so important to keep your sprouts gently moving in the breeze. This will strengthen their stalks, allow more light to pass through the canopy, and keep moisture off the surface of the soil to prevent common diseases like "damping off". The single act of fanning your seedlings will drive your success rate up so high, you'll literally be amazed at your progress.

Of course, use caution, and build up the tender little seedlings strength by adjusting the fan speed while they grow.


Step 4: Ambient Room Temperature
68 degrees, "Think Spring"

Although the seedling is warm near the heat mat and lights, as they get bigger and you start to transplant them off the mat, ambient room temperature should be gaged and provided for accordingly. Check your seed packet and shoot for the high range indicated.

Remember, basements are cold and damp; attics are hot and dry. Greenhouses and cold frames still get cold at night. If you need heaters, use them, they will speed up the growing process and save you from a surprise freeze. The inexpensive electric oil-radiator heaters are superb in small to medium sized spaces and cost very little to use. I highly recommend them to keep the temperatures stable, and increase growth rate. Stay ahead of the plant's needs by considering their ideal temperatures, and temperatures and conditions they will be heading for in the garden.


Step 5: Make Blocks

Completely dry soil blocks - 3/4Our whole site is dedicated to making great soil blocks. But, here are some tips and tricks that will help you expand your skills.

a.) Soil blocks can be made, then mostly dried, and then stored indefinitely. Choose this option when you think you might be busy with other things come spring time. Just pull out your blocks and rehydrate them from the bottom up in a bottom-watering tray. Let them soak, COMPLETELY, before seeding, and be advised these re-hydrated blocks will have the tendency to dry out faster than fresh blocks.

b.) Soil blocks can also be made and stored fresh for up to 3 months. How? The key here is to make soil blocks without any fertilizers. Then, make them, and store them in a flat or tray with out holes or drainage and completely cover or enclose them in a big black garbage bag. Store flat, no stacking, and no peeking as air and light will try to trigger algae growth, which is not bad at all. Keep sealed TIGHT for moisture control.

seed packet


Step 6: Sow Seeds.

Guru's Tip: Study the seed packet to gain chosen plant. The seed packet is your guide, use it to  navigate through the darkness.

wool-and-pepperseed in blocks


Step 6a: Secrets of Nature.

Alan Chadwick's
Planting by the Phases of the Moon
See the full report on planting by moon phases


planting moon phasesmoon phases key


The Enemy: Damping-Off

Fortunately for me, I have never once experienced damping off in 11 years of Coleman and never broke his advice. Here it is for you. May it serve you wonders for the rest of your life.

From The New Organic Grower by Eliot Coleman:

On Sterilizing your soil block mix...
"I realized early on that damping-off and similar seedling problems, which are usually blamed on unsterilized soil, are actually a function of cultural mistakes like overwatering, a lack of air movement, not enough sun, overfertilization, and so forth. Good fertile garden soil and well prepared compost contain many organisms that benefit seedling growth."

See: Watering, Compost, and Transplanting for further information on how to keep your seedlings healthy and vigorous.

Guru's Tip: If you've been prone to damping off before, you'll probably get it again, if you don't sterilize your trays, flats, mats, pots, room, etc. How? Use a 10% Household Bleach Solution in water and spray down the area with a spray bottle.


Great Recycled Ideas!

Trays, stacked cedar flat

Make some cedar trays! Inside diameter should always be 18" x 8" x 2" high.

wire rack

Using 1/2" x 1" galvanized fence rolls to air prune some blocks.
This is the art and science of soil blocking: No Plastic!

tetra brikplastic sack humidity dome
Recycled container trays

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